Clinical characteristics of labyrinthine concussion.

BACKGROUND AND OBJECTIVES: Inner ear symptoms like hearing loss, dizziness or tinnitus are often developed after head trauma, even in cases without inner ear destruction. This is also known as labyrinthine concussion. The purpose of this study is to determine the clinical manifestations, characteristics of audiometry and prognostic factors of these patients.

MATERIALS AND METHODS: We reviewed the medical records of the 40 patients that had been diagnosed as labyrinthine concussion from 1996 to 2007. We studied the hearing levels in each frequency and classified them according to type and degree of hearing loss. Rates of hearing improvement were evaluated according to age, sex, hearing loss type, degree and presence of dizziness or tinnitus. To find out any correlation between hearing improvement and these factors, we used χ(2) test or Fisher's exact test.

RESULTS: Bilateral hearing loss was observed in 22 patients, and unilateral hearing loss in 18 patients. There were 4 (6.5%) ascending, 34 (54.8%) descending, 24 (38.7%) flat type hearing loss, which indicated hearing loss was greater in high frequencies than low frequencies. Among 62 affected ears, 20 (32.3%) gained improvement, and it was achieved mainly in low frequencies. There were only 2 ears with dizziness in 20 improved ears and among 20 dizziness accompanied ears, also only 2 ears were improved.

CONCLUSIONS: High frequencies are more vulnerable to trauma than low frequencies. The hearing gain is obtained mainly in low frequencies, and association with dizziness serves poor prognosis.